The present invention relates to a laminated bottle that has a delaminatable inner layer and an outer layer, wherein the outer layer has an inner surface on which the inner layer is laminated and has a ventilation hole to take ambient air in itself. The invention also relates to a pumping container that comprises the laminated bottle and may be a comb-product or the like, the laminated bottle serving as an reservoir charged with a content such as a hair-dyeing agent.
Japanese Patent Laying-Open Gazette No. Hei. 4-267727 discloses a multi-layered container, which is designed such that ambient air is inhibited from entering the container through a mouth and its content is discharged by the pumping action of an inner layer and an outer layer. This container consists of a bottle and a cap. The bottle is composed of an impermeable inner layer and a squeezable outer layer. The cap is attached to the mouth of the bottle. The inner layer can be readily delaminated from the outer layer in which ventilation holes are formed such that the ambient air can communicate with the space between the layers. The cap has a check valve incorporated therein. Therefore, the inner layer of this bottle will naturally shrivel with a decrease in its content, with the ambient air flowing into the space through said holes so that only the outer layer can restore and maintain its normal configuration. Owing to this feature, its content remains satisfactory in quality, from the beginning to end of use, without being adversely affected by ambient air or external light beams.
The multi-layered container in the prior art has a film tag adhered in part to the rim of the ventilation hole, and the tag larger than the hole is disposed inside the outer layer. Such a kind of ventilation valve will allow air to flow inwards penetrating only the outer layer from outside. With the container being gripped by a user, the ventilation hole will be closed with the valve due to an increasing inner pressure so as not to allow any amount of air to leak out from the interlayer space. Such a depressed outer layer will raise the interlayer air pressure to thereby depress in a centripetal direction the inner layer so as to exude the content out of the container.
The prior art method comprising the steps of preliminarily blow molding or thermally forming the outer layer and subsequently integrating it with the inner layer does however require so many steps as increasing manufacture cost of the multi-layered pumping containers and lowering yield thereof. In an alternative method, the laminated bottle with the ventilation hole formed solely in the outer layer may be molded, and the ventilation valve is then attached to the hole. However, this method will also increase the number of steps and necessary parts, inevitably resulting in a higher manufacture cost.
The present invention provides a laminated bottle having a delaminating inner layer, and also provides a pumping container comprising the laminated bottle such that at least one ventilation hole is opened or closed by and/or with the inner layer itself to take ambient air in a space between the inner and outer layers, without needing any discrete or additional suction valve. This feature of the invention will be effective not only to decrease the number of necessary parts but also to simplify the structure, thus abridging manufacture process and reducing manufacture cost. Further, the inner layer may have a closing portion capable of elastic recovery to temporarily close the at least one ventilation hole formed in the outer layer, hereby the air between these layers is more reliably prevented from leaking out.
In accordance with the present invention, the laminated bottle may have the delaminating inner layer laminated on the inner surface of the outer layer and capable of exfoliation therefrom, wherein the at least one ventilation hole is formed in the outer layer to allow ambient air to flow into the space between the outer and inner layers. The ventilation hole in the outer layer may be normally closed with a closing portion of the inner layer from inside. The closing portion may function as a valve that is capable of inward deforming due to atmospheric pressure in response to a negative pressure appearing in the space between the inner and outer layers. Because the closing portion provided as an integral part of the inner layer functions as a valve in the laminated bottle of the invention, any discrete or extra valve body need not be mounted, therein. Despite lacking in any discrete valve body, a user does not have to shut the ventilation hole with his or her fingers when he or she will squeezes the bottle. As content in the bottle gradually flows or exudes out, the closing portion will be pressed outwards by the content, hereby it will be spontaneously close the ventilation hole.
Preferably, the closing portion of the inner layer may have elasticity for shape recovering so as to close the ventilation hole. Such a closing portion will restore its natural configuration to close again the outer layer ventilation hole, upon disappearance of negative pressure within the interlayer space due to inflow of a sufficient amount of ambient air into said space. Thus, the bottle""s outer layer may be squeezed subsequently or later, surely inhibiting the air from flowing out of the interlayer space.
The laminated bottle of the invention may comprise of a body and a mouth, by forming the outer and inner layers to comprise respective body parts and respective mouth parts. Preferably, the at least one ventilation hole is formed in the outer layer""s mouth part, and the inner layer is made thicker at its mouth part than its body part so as to act as the portion for closing said hole. This structure will enable a cap fitted on the bottle to hide the ventilation hole, affording a pleasant appearance to the product, viz., container. In contrast with such the mouth part of inner layer made thicker to be capable of restoring its normal shape to close said hole, the thinner and film-shaped body part of inner layer will readily deflate in the course of discharging the content. A parison to be blow molded for forming the bottle may be of a uniform thickness from its mouth part to body part, and by stretching only the body part of the parison in the blow molding step, it is possible to provide the bottle that the body part of the inner layer is of a film-like shape and the mouth part of the inner layer is of a layer thickness such as the same has elasticity for shape recovery. This means that any extra step or additional process is not needed herein to give the inner layer portion a shape capable of performing itself as a kind of valve body.
The mouths of outer and inner layers may be of a cylindrical shape (whether round or elliptic), the ventilation hole may be formed in the mouth part of the outer layer, and the mouth part of the inner layer may act as the closing portion as described above. If the inner layer""s mouth part as closing portion is cylindrical, its elastic recovery will be enhanced to surely seal the ventilation hole.
In the described bottle of this invention, a bottom of the inner layer may comprise a flange fixed on and/or engaging with a bottom of the outer layer, securing these bottoms to each other to prevent the inner layer""s lower end portion from curling up. Preferably, the flange may be formed when molding a inner preform for forming the inner layer by injecting a molten resin to an interior of an outer preform for forming the outer layer through a through-hole that is previously formed in a bottom of the outer preform.
The laminated bottle having the mouth in the invention may be utilized to construct any pumping containers for varied uses, if a cap comprising a check valve is attached to the mouth. Such the pumping container provided herein may substantially comprise of the laminated bottle and the cap fixed on the mouth, wherein the body part of the bottle""s outer layer is capable of being deformed so as to deflate. Also, the cap may have an outlet orifice for discharging the content stored within the inner layer out of the inner layer, and a check valve may be attached to the outlet orifice. The outer layer may be shaped in any proper fashion such as a cylinder squeezable in radial direction or as a tubby structure to be compressible in axial direction.
The laminated bottle may be formed by an appropriate method such as injection molding and/or blow molding. Examples of the blow molding are the direct blow molding method and the injection-stretching-blow molding method. Preferably, the latter method may be employed to produce precise molded products.
Also, the present laminated bottle may be manufactured by a method that comprises of the step of injection molding an outer layer preform, the step of injention molding an inner layer preform inside the outer layer preform, and the step of blow molding a parison composed of these preforms. Further, the ventilation hole may be formed at the step of injection molding the outer layer preform, and at least one pin will be inserted into the hole when molding the inner preform.
In this method of making the laminated bottles, the ventilation hole is formed at the step of injection molding the outer layer preform, lest the inner layer should not be injured. Also, it is no longer necessary to manually punch the holes in the outer layers one by one after injection molding same, thus improving manufacture efficiency.
Those outer and inner layers may have respective molded configurations each composed of a body portion and a mouth portion to constitute a bottle. To protect the mouth portions of the outer and inner layers from separation from each other, a relatively large thickness of the inner layer may for instance be effective. The outer layer will be rendered so easy to squeeze as enabling it to readily deform itself elastically if depressed with a user""s hand, or alternatively may be rigid in the event that a pump for sucking the content of bottle would be attached to the mouth portion.
In the method of making the bottles, the parison may preferably be blow molded in such a way that the stretching of the parison is effected below its region where the ventilation holes are located. The ventilation holes in this case are protected well from deformation which the step of stretching would cause, thereby preventing the resin fractions around the holes from flowing therein to clog same. Stretching does not take place around the ventilation holes, so that a portion of the inner layer surrounding the hole will have its wall thickness as thick as the same of the inner preform. Thus, the body part of the inner layer for containing the liquid content (i.e., the charged content) can be thinner than the mouth part of the inner layer to be of a film-like shape and/or structure. At the same time, a portion of the inner layer, which is located adjacent to the ventilation hole, may be thicker than the body part of the inner layer so as to be capable of elastic recovery. The inner layer constructed to naturally close the ventilation holes will however be depressed readily apart from them by external air pressure. It will deform itself inwardly so as to open those holes when ambient air is allowed to enter the interlayer space through them. The ventilation holes behave as if they were valves, so that it is no longer necessary to incorporate any extra or additional valve that would increase the number of constituent parts and raise manufacture cost.
In this method of making the laminated bottles described above, various appropriate manners may be employed to make the ventilation holes solely in the outer layer. For example, the outer layer preform may be injection molded using a cavity segment and a core segment, and then be left to remain in the cavity segment. The inner layer preform will subsequently be injection molded using the cavity segment in combination with another core segment substituting for the first-mentioned core segment. In this mode of the method, the ventilation holes may be formed by causing pins to contact the first core segment before the resin becomes hard at the step of injection molding the outer layer preform. The ventilation holes are allowed to remain closed with the pins while the inner layer preform is being injection molded.
Such a method described above may be conducted using the following apparatus. Namely, this apparatus will be used to produce a parison to be blow molded into a laminated bottle. The parison is composed of an outer and inner layer preforms and has ventilation holes only in the outer layer at desired portions thereof. A mold constituting this apparatus may comprise a cavity segment and two discrete core segments, wherein one of the core segments is selected and fastened to the cavity segment so as to mold the outer layer preform at first, and subsequently the other core segment will be used to mold the inner layer preform. Further, this apparatus may comprise pins in connection with the cavity segment in order to form the ventilation holes. Those pins can shift themselves between their projected position contacting the first-mentioned core segment and their retracted position embedded in the cavity segment.
Although the pins in the described example to form ventilation holes are located in connection with the cavity segment, they may alternatively be disposed in a lip segment if the apparatus has same. In this case, the pins at their retracted position will be enclosed with said lip segment.
Further in an alternative method of forming ventilation holes only in the outer layer preform, this preform will be molded in an injection mold and then removed therefrom. This outer layer preform is then inserted in a further and separate injection mold for forming the inner layer preform so that pins equipped in connection with the further mold are inserted from outside into rough ventilation holes that have been formed. Inner ends of those pins will be brought into flush with the inner surface of the outer layer preform, before the inner layer preform is injection molded.
Such an alternative method described above may be conducted using the following apparatus to produce a parison to be blow molded into a laminated bottle. This parison will also be composed of an outer and inner layer preforms and have ventilation holes only in the outer layer at desired portions thereof. This apparatus may comprise an injection mold for forming the outer layer preform and a further injection mold for forming the inner layer preform. Pins for forming the ventilation holes are provided in the first-mentioned mold so as to shift themselves between their projected and retracted positions. The secondly-mentioned mold comprises pin-shaped stoppers that are to be inserted from outside into the ventilation holes previously formed in the outer layer preform.
The method described above addresses parisons that are to be blow molded to give the delaminating types of laminated containers. However the present invention is not restricted thereto but is applicable to a variety of injection molded laminated articles (such as laminated parisons) each composed of two or more resin layers. In other words, the present invention proposes a method of making ventilation holes solely in an outer layer of an injection molded laminated product having an inner layer inside the outer layer. The method may comprise the steps of injection molding the outer layer and then molding the inner layer so that the ventilation holes are formed during the step of injection molding the outer layer, wherein the inner layer is injected while pins remain inserted in the ventilation holes.
The parison-forming mold employed in the apparatus and method of the present invention may comprise at least one cavity segment and at least two core segments, larger and smaller. This mold may further comprise a projectable member that is mounted in the cavity segment so as to contact the side surface of the larger core segment. An appropriate means may also be incorporated to drives pins preferably serving as the projectable members.
When molding the outer layer preform in the described mold, this preform""s portions where the projectable members are temporarily located can not be filled with a resin for forming this preform. As a result, those portions will define the ventilation holes penetrating that preform from an outer surface to inner surface thereof This means that the ventilation holes as air passages can be formed already at the same time as the outer layer preform is molded.
The projectable member incorporated in the mold described above may be held in and by the lip segment so as to be capable of contacting the core segment""s side face. Alternatively, that member may be held in and by the core segment so as to contact the inner surface of the cavity segment or the lip segment. In any case, the projectable member may preferably be located below a threaded portion surrounding a mouth of the container that will be produced from the preform.
Also, this method of making the laminated bottles comprises the step of forming one or more ventilation holes that penetrate the outer layer preform from an outer surface to inner surface thereof, at the same time as this preform is molded. The ventilation holes are thus formed already at the step of forming the outer layer preform. The present method now eliminates the problem inherent in the prior art that has been injuring the inner layer when forming the ventilation holes in the outer layer during the blow molding step. Further, works for manually piercing such holes one by one in the injection molded outer layer are no longer necessary, thus enhancing manufacture efficiency.
The delaminating inner layer preform is formed herein onto the inner surface of the outer layer preform in such an advantageous manner that their portions located below the ventilation holes are subsequently stretched for orientation.
According to this method, inner layer portions corresponding to the ventilation holes maintain an original wall thickness, so that each of such relatively thickened portions may function as a kind of valve body cooperating with the ventilation hole. Thus, manufacture process becomes simpler and less expensive, as compared with the case of employing extra and discrete valves.
Also in the present method, an inner end of the projectable member may be located substantially in flush with the inner surface of the outer layer preform when the inner layer preform is molded using the mold described above.
Due to this feature, a resin forming the inner layer preform can be prevented from flowing into portions that have to form the ventilation holes in the outer layer preform.
In the manufacturing methods described above, the ventilation holes may preferably be formed below a threaded portion of the outer layer preform.
The laminated bottle with the flange disposed in the inner layer""s bottom may be produced by the following manufacturing method. In the method providing laminated bottles whose peripheral walls are composed each of an outer layer and an inner layer disposed therein, a resin of the inner layer has a lower melting point than that of the outer layer. In detail, the outer layer preform will preliminarily be injection molded, and subsequently the inner layer preform is injection molded on the inner surface of the outer layer preform by using another resin whose melting point is lower than that of the outer layer resin. The parison composed of the outer and inner layer preforms will finally be blow molded. The through-hole mentioned above may be formed in the outer layer preform when this preform is injection molded, by such an arrangement that a gate penetrating the cavity segment for injection of the second resin does face the through-hole. In this case, a molten resin will be guided through this gate and the through-hole into the interior of the outer layer that has been placed in the mold for injection molding the inner layer. In this invention, the inner layer preform is, molded after the outer layer preform has been molded, as repeatedly discussed above. Therefore, even if the inner layer preform is made of a polyolefin or the like material and the outer layer preform is made of a xe2x80x98PETxe2x80x99, an xe2x80x98EVOHxe2x80x99 or the like resin, these two kinds of resins will not intermix with each other but be demarcated from each other. Consequently, the laminated bottle made by this method has the inner layer ready to exfoliation from the outer layer during use, thus protecting a liquid content in this bottle from change in its chemical properties. Further, the through-hole in the outer layer preform may be produced by putting a pin towards the gate so as to bring a free end of the pin into contact with the gate, after injection of the resin though the gate. The gate in this case will be sealed up with the pin lest any gate flashes should be produced, thus making it unnecessary to sever them from container bodies.
The flange mentioned hereinbefore is produced of the same resin as the inner layer preform so as to be disposed outside the through-hole during the injection molding of the inner layer preform. The flange is integral with a resin mass disposed in the through-hole and is therefore integral with the inner layer preform itself. Such a flange is considerably larger than the through-hole in diameter so that the inner layer can be securely fixed in part in the outer layer. Due to this feature, a stretching rod used at the step of stretching-blow-molding will be prevented from peeling the inner layer off the outer layer. If such a flange is located at the bottom of the bottle, the inner layer will be allowed to delaminate from the outer layer during use, without giving rise to the problem of curling up of the inner layer""s lower end portion. Tie xe2x80x98flangexe2x80x99 may either be formed in flush with the outer surface of the outer layer, or alternatively, jutting outwards from the through-hole.
In case of using the method to manufacture laminated bottles each having a delaminating inner layer, a resin of the inner layer preform may preferably be projected out of the through-hole of the outer layer preform so as to form a stud-shape protrusion, before injection molding the inner layer preform. A stretching rod used to carry out the step of longitudinally stretching the parison will collapse the protrusion stud-shaped and made of the resin forming the inner layer. The longitudinal stretching conducted at the step of blow molding will press the bottom of the parison to collapse the protrusion to reform it as a flange disposed outside the bottom of outer layer. The inner and outer layers are thus fixedly secured to each other at their bottoms. In this way, any additional step is not needed to integrate these layers with each other at their bottoms.
In addition, the injection molding of the inner layer preform may be conducted such that a plurality of thickened portions are formed integral with the preform in such a fashion that each portion extends longitudinally and at angular intervals. Thus, the blow molded laminated bottles will have each the inner layer that is formed integral with pillaror rib-shaped thickened portions. Those thickened portions will provide a moderate resistance to deformation such that the inner layer is inhibited from any abrupt and irregular delamination from the outer layer. Flat regions each interposed between the linear thickened portions of the inner layer will be caused to make a gradual and inward displacement, to thereby ensure uniform shrivelage and deformation of the inner layer over full height thereof in each bottle. Neither a middle portion of the inner layer nor an upper end portion thereof (located close to the bottle mouth) will shrivel sooner than the lower portion of the layer. Thus, the latter portion is protected from being sealed not to exhaust a liquid content. Since the inner layer preform is injection molded herein, the forming of such thickened portions can easily be done during the injection molding step in a reliable manner to give products each having a uniform internal texture.
Alternatively, it is possible to provide the inner layer preform with a barrel-shaped part that has a thickened region extending in a helical direction. This region may be a helical protrusion formed integral with the inner surface of the barrel-shaped part. Alternatively, a helical recess may be formed in and along the inner surface of the outer layer preform, and then the inner layer is injection molded inside the outer layer preform to produce such a helically thickened region.
Also, the injection mold used herein to produce the outer layer preform with a closed bottom may comprise the cavity segment in combination with a modified core segment having the pin. This pin is intended to contact an inner surface of the closed bottom of the cavity segment. Such a type of the mold may also be suited to preparation of the outer layer preform in the present invention. If this mold is employed to form an outer layer, then a space occupied by the pin can not be filled with any amount of the resin of this preform. Thus a through-hole will be produced to extend from an outer surface to inner surface of the outer layer preform. In short, the hole is formed through the bottom of this preform while molding same.
Alternatively, the injection mold just described above to produce the outer layer preform having the closed bottom for constituting the laminated container may comprise the at least one core segment and the at least one cavity segment, with the latter segment having a pin to contact the closed end of the former segment.
Each of these injection molds may have the pin capable of projecting into and being retracted from a gate so that this gate facing the pin is clogged therewith.
In summary, the laminated bottle of the invention described above may be produced utilizing the following manufacturing apparatus. This apparatus is composed of a device for injection molding the outer layer, a further device for injection molding the inner layer, and a still further device for blow molding them. A cylindrical outer layer pre-form having a bottom and a through-hole formed through the bottom will be injection molded by the first-mentioned device. The further device for injection molding the inner layer injects an inner layer preform inside the outer layer preform. The still further device blow molds a parison that is formed with a bottom and composed of the outer and inner layer preforms, while biaxially stretching the parison longitudinally and transversely in such a way that the inner layer delaminatable from the outer layer is laminated on the inner surface thereof to provide a laminated container. The device for injection molding the inner layer preform may have a gate for passing a molten resin through the hole to thereby inject it from outside into the outer layer preform. The gate may be spaced outwards from the through-hole. Using these devices, the gate formed in a mold for injecting the inner layer is spaced a distance from the through-hole of the outer layer preform. A portion of the resin for the inner layer preform protrudes out of the hole and solidifies to be left there, when injection molding the inner layer preform with the further device. At the step of longitudinally and circumferentially blow molding the parison using the still further device, a stretching rod will collapse this protrusion when the parison with bottom is longitudinally stretched. Subsequently, the resin will spread on the outer surface of the outer layer bottom to engage the inner layer with the outer one at the bottom of the container. It is possible to form the inner layer using such a resin as having a lower melting point than that of the outer layer. In other word, it is now possible to choose the most preferable resin because the molten resin of the inner layer preform is introduced through the hole already formed in the bottom of the outer layer preform, so as to flow on and along the inner surface thereof.